Method and device for production of a pre-fabricated cast concrete element

ABSTRACT

Device for producing a prefabricated cast concrete element having a plurality of central structural elements each comprising two parralel welded wire lattice mats, straight bridging wires welded at each end to the two wire lattice mats holding the wire lattice mats at a predetermined mutual separation and an insulating member penetrated by the bridging wires arranged with its cover surfaces parallel to the wire lattice mats and at a predetermined distance to the latter and having two concrete shells which each adjoin the insulating member and completely enclose the wire lattice mats of the structural elements, characterized in that a plurality of central structural elements are each arranged with their narrow sides abutting one another with selectable spacing between two shuttering walls and the spaces between the insulating members of the structural elements and the shuttering walls completely filled out with concrete.

This application is a U.S. National Phase Application under 35 U.S.C.371 of International Application PCT/AT00/00309 (not published inEnglish) filed Nov. 17, 2000.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a method and a device for producing aprefabricated cast concrete element having a plurality of centralstructural elements each comprising two parallel welded wire latticemats, straight bridging wires welded at each end to the two wire latticemats holding the wire lattice mats at a predetermined mutual separationand an insulating member penetrated by the bridging wires arranged withits cover surfaces parallel to the wire lattice mats and at apredetermined distance from the latter and having two concrete shellswhich each adjoin the insulating member and completely enclose the wirelattice mats of the structural elements.

2. Description of the Prior Art

WO 94/28264 discloses a structural element of this generic categorywhose two concrete shells are sprayed in layers onto the cover surfacesof the insulating member by the wet or dry method preferably at thepoint of use of the prefabricated wall. In the case of very thickconcrete shells pouring of the shells using site-mixed concrete is alsopossible. In doing this it is disadvantageous that the layeredapplication of the concrete shell is very time-consuming and, moreover,the bonding of the individual layers is not always ensured.

SUMMARY OF THE INVENTION

It is an object of the invention to avoid the disadvantages describedand to provide a method and a device for producing a prefabricatedelement which allow in simple manner the production of a prefabricatedelement of the type specified at the outset and the adaptation of thedimensions of the prefabricated element to differing staticrequirements.

The method according to the invention is characterised in that aplurality of central structural elements each with their narrow sidesabutting one another are arranged at a variable distance between twoshuttering walls and the spaces between the insulating members of thestructural elements and in that the shuttering walls, as known per se,are completely filled out with concrete.

It should be mentioned that it is known from the U.S. Pat. No. 4,702,053in connection with a method of another kind to fill the spaces betweenthe insulating member of the structural elements and the shutteringwalls.

The concrete shells are preferably cast in several working operations,wherein consecutive work operations are performed before the concrete iscompletely hardened.

Preferably, the method is employed according to the invention forproducing vertical prefabricated walls. In doing so, to form a verticalprefabricated wall a plurality of structural elements is arrangedaccording to the invention each in abutment beside one another in thevertical and horizontal direction and the lower structural elements areeach anchored in fixed position in a base plate, wherein structuralelements adjoining in the horizontal direction are arranged in alignmentin a straight line and/or along a curved line and/or also at any desiredangle relative to one another.

A device destined for carrying out the described method is characterisedaccording to the invention in that for producing the spacings betweenthe structural elements and the shuttering walls a plurality of spacingmembers composed of rustproof materials is provided between theshuttering walls and the wire lattices and in that the shuttering walls,as known per se, are composed of a plurality of sections connectable toone another.

According to a preferred embodiment of the device distance pieces areprovided as the spacing members which with the aid of cruciform slitscan be plugged onto selected points of intersection of the longitudinaland transverse wires of the wire lattice mats and brace themselves bytheir ends against the shuttering walls.

According to a further characteristic of the invention elongated spacingmembers are provided which during casting of the concrete shells can bepulled out from the spaces between structural elements and theshuttering walls.

BRIEF DESCRIPTION OF THE DRAWINGS

Other characteristics and advantages of the invention are explained inmore detail below on the basis of exemplified embodiments with referenceto the drawings. These show:

in FIGS. 1 a, 1 b and 1 c an arrangement according to the invention withdistance pieces for carrying out the method in cross section, in planview and in front view;

in FIGS. 2 a, 2 b and 2 c a distance piece viewed from below, in sideelevation and in plan view;

in FIGS. 3 a and 3 b a finished cast vertical prefabricated wallproduced according to the arrangement in FIGS. 1 a and 1 b in sectionand in plan view;

in FIG. 4 a metal spacing plate;

in FIGS. 5 a and 5 b another arrangement according to the inventionmaking use of the metal spacing plate shown in FIG. 4;

in FIGS. 6 a and 6 b a finished cast vertical prefabricated wallproduced according to the arrangement in FIGS. 5 a and 5 b in sectionand in plan view;

in FIGS. 7 a and 7 b another arrangement according to the inventionusing spacing tubes and

in FIGS. 8 a and 8 b a finished cast vertical prefabricated wallproduced according to the arrangement in FIGS. 7 a and 7 b in sectionand in plan view.

DETAILED DESCRIPTION OF THE DRAWINGS

The arrangement illustrated in FIGS. 1 a and 1 b consists of a baseplate 1, two shuttering walls 2 or 2′ and a plurality of centralstructural elements 3. Each structural element 3 is built up by way ofexample in accordance with WO 94/28264 and consists substantially of anouter and an inner wire lattice mat 4 or 4′ which are arranged parallelto one another at a predetermined distance. Each wire lattice mat 4 or4′ is composed of a plurality of longitudinal wires 5 or 5′ and of aplurality of transverse wires 6 or 6′ which cross one another and arewelded to one another at the points of intersection. The mutual spacingof the longitudinal wires 5, 5′ and the transverse wires 6, 6′ relativeto one another and the diameter of the lattice mat wires 5, 5′, 6, 6′ ischosen in accordance with the static requirements imposed on theprefabricated wall to be produced. The spacings are preferably chosen tobe of equal size and lie by way of example in the range of 50 to 100 mm.The diameters of the longitudinal and transverse wires 5, 5′ or 6, 6′lie by way of example in the range of 2 to 5 mm.

The surface of the lattice mat wires 5, 5′, 6, 6′ may within the scopeof the invention be smooth or ribbed. The two wire lattice mats 4, 4′are connected to one another by a plurality of bridging wires 7 to forma dimensionally stable latticework. The bridging wires 7 are each weldedat their ends to the wires 5, 5′, 6, 6′ of the two wire lattice mats 4,4′. The bridging wires 7 are arranged to slope alternately in oppositedirections, ie like trelliswork, by which means the latticework isreinforced against shear stresses. The spacings of the bridging wires 7relative to one another, their diameter and their distribution in thestructural element 3 depend on the static requirements imposed on theprefabricated wall to be produced. The diameter of the bridging wires 7lies by way of example in the range of 2 to 6 mm and in the case ofstructural elements having thin longitudinal and transverse wires ispreferably chosen on grounds of the greater rigidity of the structuralelement 3 to be greater than the diameter of the longitudinal andtransverse wires 5, 5′ or 6, 6′ of the wire lattice mat 4, 4′. Thebridging wires 7 can be provided within the scope of the invention witha corrosion protection layer which is composed by way of example of alayer of zinc and/or a layer of plastic. The use of bridging wires 7composed of grades of stainless steel is likewise possible within thescope of the invention. The longitudinal and transverse wires 5, 5′ or6, 6′ of the wire lattice mats 4, 4′ as well as the bridging wires 7 mayhave any desired cross-section. For example, the cross-sections may beoval, rectangular, polygonal or square.

The three-dimensional latticework formed by the two wire lattice mats 4,4′ and the bridging wires 7 is a three-dimensional reinforcing elementwhich is able to absorb corresponding shear and compressive forces. Forthis reason both the longitudinal and transverse wires 5, 5′ or 6, 6′are welded to one another as is customary in reinforcing mats and thebridging wires 7 are welded to the lattice mat wires 5, 5′, 6, 6′ withadherence to a minimum strength for the welded joints. In order to beable to fulfil the function of a three-dimensional reinforcing elementthe lattice mat wires 5, 5′, 6, 6′ and the bridging wires 7 mustadditionally be composed of suitable materials and possess appropriatelevels of mechanical strength.

Arranged in the space between the wire lattice mats 4, 4′ at a specifieddistance from the wire lattice mats 4, 4′ is an insulating member 8whose cover surfaces 9 or 9′ run parallel to the wire lattice mats 4,4′. The insulating member 8 serves the purpose of thermal insulation andsound insulation and consists by way of example of foam plastics, suchas polystyrene or polyurethane foam, of foamed materials based onnatural and synthetic rubber, lightweight concrete, such as autoclavedor gas concrete, of porous plastics, of porous materials based onnatural and synthetic rubber, or of mineral and glass wool. Within thescope of the invention the insulating member 8 may also be composed ofbiological plastics, for example algal foam which is produced fromfoamed algae or algal cellulose.

The position of the insulating member 8 in the structural element 3 isdetermined by the bridging wires 7 running at a slant which pass throughthe insulating member 8. The thickness of the insulating member 8 isfreely selectable and lies by way of example in the range of 20 to 200mm. The spacings of the insulating member 8 relative to the wire latticemats 4, 4′ are likewise freely selectable and are selected in accordancewith the desired wall thickness of the prefabricated wall. Within thescope of the invention the insulating member 8 may also be arrangedasymmetrically with respect to the two wire lattice mats 4, 4′. Withinthe scope of the invention one or both wire lattice mats 4, 4′ mayproject laterally over the insulating member 8 on one or more sides.

Distance pieces 10 are pushed into some points of the intersection ofthe longitudinal and transverse wires 5, 6, or 5′, 6′ of the wirelattice mats 4, 4′. As FIGS. 2 a, 2 b and 2 c show, the distance pieces10 have a head 12 provided with two slits intersecting at right anglesand a plurality of feet 13 at the opposite end. The distance pieces 10are made of rustproof material, preferably of plastic. The width of theslit 11 is smaller than the diameter of the lattice mat wires 5, 5′, 6,6′ to ensure clamping of the distance pieces 10 at the points ofintersection of the lattice mat wires 5, 5′, 6, 6′. The depth of theslits 11 and the length of the feet 13 are matched to the desiredspacing of the shuttering walls 2, 2′ from the wire lattice mats 4, 4′.The spacings lie by way of example in the range of 10–30 mm, whereinwithin the scope of the invention the shuttering walls may be arrangedsymmetrically and, as illustrated by dotted lines in FIG. 5 a,asymmetrically with respect to the structural element 3. The feet 13 aretapered towards the end.

As illustrated in FIGS. 1 b and 1 c a plurality of structural elements 3and a plurality of shuttering walls 2, 2′ adjoin one another in thehorizontal direction at abutments S₁ and S₂. For construction of acomplete vertical prefabricated wall a plurality of structural elements3 and a plurality of shuttering walls 2, 2′ adjoin one another also inthe vertical direction at abutments S shown in FIGS. 1 a and 1 c.

The vertical prefabricated wall is constructed as follows. On the baseplate 1 first of all the lower structural element 3′ provided with thecorresponding distance pieces 10 and all neighbouring structuralelements 3′ likewise provided with distance pieces 10 are each set upstanding vertically on their narrow sides. In doing so it is possiblewithin the scope of the invention to arrange the structural elements 3′in alignment in a straight line or along a curved line or also at anydesired angle relative to one another, wherein any desired combinationsof these arrangements within a prefabricated wall are possible withinthe scope of the invention. The position of the lower structuralelements 3′ on the base plate 1 is fixed by a plurality of rod-shapedreinforcing irons 14 which project by their free ends into the spacesbetween the insulating member 8 and the wire lattice mats 4, 4′ and areanchored, for example cast in place or screwed in, by their other endsin the base plate 1. Subsequently, in further working steps morestructural elements 3 are arranged in the vertical direction and theouter and the inner shuttering walls 2 or 2′ are built up. Depending onthe height of the prefabricated wall the shuttering walls 2, 2′ consistof a plurality of sections which are connected, preferably bolted, toone another. All shuttering walls 2, 2′ brace themselves against thefeet 13 of the distance pieces 10. Concrete is poured into the spacesbetween the insulating members 8 of the structural elements 3, 3′ andthe shuttering walls, 2, 2′. After the concrete has hardened, theshuttering walls 2, 2′ are removed and the finished cast wall with anouter concrete shell 15 and an inner concrete shell 15′ illustrated insection and in plan view in FIGS. 3 a and 3 b respectively is produced.Since the feet 13 of the distance pieces 10 terminate in a point at thebottom and, moreover, the distance pieces 10 are made of rustproofmaterial, the distance pieces 10 can remain in the concrete shells 15,15′ without impairing the visual appearance of the visible exteriors ofthe concrete shells 15, 15′.

In FIG. 4 another thin spacing member 16 of strip-like construction isillustrated. The metal spacing plate 16 consists of a sheet metal stripwhich is composed of rustproof material, for example stainless steel orplastic. The metal spacing plate 16 possesses an elbow 17 on both sidesand a plurality of slits 18 running crosswise relative to thelongitudinal extension of the metal spacing plate 16 to accommodatefixing wedges 19. The width of the metal spacing plate 16 and thedimensions of the elbows 17 are substantially determined by thedimensions of the wire lattice mats 4, 4′ as set out below withreference to FIGS. 5 a, 5 b and 6 a and 6 b. The length of the metalspacing plate 16 and the number and position of the slits 18 in themetal spacing plate 16 are determined by the overall thickness of theprefabricated wall to be produced and the required thicknesses of theconcrete shells 15, 15′ of the prefabricated wall, ie the distances ofthe shuttering walls 2, 2′ or 2″ from the surfaces 9, 9′ of theinsulating member 8 as set out below with reference to FIGS. 5 a, 5 band 6 a and 6 b.

The construction of the prefabricated wall corresponds substantially tothe procedure already described, wherein the distance pieces 10 areomitted. Serving as spacing elements are the metal spacing plates 16which, as illustrated in FIGS. 5 a and 5 b, are fitted in the followingmanner.

In the course of building up the shuttering walls 2, 2′ or 2″, which isdone by analogy with the procedure already described, the metal spacingplates 16 are inserted between the sectional walls of the shutteringwalls, whereby the metal spacing plates 16 are punched through theinsulating members 8 of the structural elements 3, 3′. The metal spacingplates 16 must possess sufficient rigidity to prevent bending of themetal spacing plates 16 when they are pushed through the insulatingmember 8. The metal spacing plates 16 are pushed in so far until theirelbows 17 rest against the longitudinal wires 5′ of the inner wirelattice mat 4′. The fixing wedges 19 are then hammered into thecorresponding slits 18 and in that way the shuttering walls 2, 2′ or 2″are fixed in position relative to the structural elements 3, 3′.

Concrete is poured into the spaces between the insulating members 8 ofthe structural elements 3, 3′ and the shuttering walls 2, 2′ or 2″.After the concrete has hardened the shuttering walls 2, 2′ or 2″ areremoved and the finished cast wall with the outer concrete shell 15 andthe inner concrete shell 15′ illustrated in FIGS. 6 a and 6 b in sectionand in plan view respectively is produced. The wedges located outsidethe concrete shells 15, 15′ are removed and the parts of the metalspacing plates 16 projecting out of the concrete shells 15, 15′ areeither cut off or bent over.

In FIGS. 7 a and 7 b another exemplified embodiment for the constructionof the shuttering walls 2, 2′ is illustrated. The construction of theprefabricated wall corresponds substantially to the procedure alreadydepicted in FIGS. 1 a and 1 b, wherein the distance pieces 10 arereplaced by spacing tubes 21.

Concrete is poured into the spaces between the insulating members 8 ofthe structural elements 3, 3′ and the shuttering walls 2, 2′. Duringpouring and hardening of the concrete the spacing tubes 21 are withdrawnstepwise from the still soft concrete just so far that the structure ofthe shuttering walls remains guaranteed. Prior to the final hardening ofthe concrete the spacing tubes 21 are withdrawn completely. Aftercomplete hardening of the concrete the shuttering walls 2, 2′ areremoved and the finished cast wall with the outer concrete shell 15 andthe inner concrete shell 15′ illustrated in FIGS. 8 a and 8 b in sectionand in plan view respectively is produced.

It is evident that the exemplified embodiments described may be modifiedin various ways within the scope of the general inventive idea; it ispossible in particular to construct the clamping parts of the distancepieces differently. It is likewise possible within the scope of theinvention to use other suitable spacing members.

It is further possible within the scope of the invention to use themethod and the devices to produce horizontally extending prefabricatedceilings also. In this case the outer structural elements are anchoredwith the aid of suitable reinforcing elements using the prefabricatedvertical walls already erected. Within the scope of the invention thesereinforcing elements may consist of anchoring rods and/or reinforcingirons and/or reinforcing mats and/or reinforcing strips. It may benecessary to attach additional shuttering elements in order to preventlateral run-off of the concrete when casting the concrete shells of theprefabricated horizontal ceilings.

1. A device for producing a prefabricated cast concrete element,comprising: a plurality of central structural elements, each of theplurality of central structural elements comprising two parallel weldedwire lattice mats, straight bridging wires welded at each end to the twowire lattice mats holding the wire lattice mats at a predeterminedmutual separation and an insulating member penetrated by the bridgingwires arranged with its cover surfaces parallel to the wire lattice matsand at a predetermined distance to the wire lattice mats; shutteringwalls arranged on opposing sides of said plurality of central structuralelements, each of said shuttering walls comprising a plurality ofsections connectable to one another; and a plurality of spacing memberscomposed of rustproof materials arranged and dimensioned for defining aspacing between each of said plurality of structural elements and saidshuttering walls for receiving concrete for forming concrete shells,wherein the wire lattice mats comprise longitudinal and transverse wiresand said spacing members comprise spacing elements having cruciformslits arranged and dimensioned for receiving selected points ofintersection of said longitudinal and transverse wires of said wirelattice mats and having ends opposing said cruciform slits bracedagainst said shuttering walls.
 2. The device of claim 1, wherein each ofsaid spacing elements is composed of plastic and has feet taperingtowards the end.
 3. A device for producing a prefabricated cast concreteelement, comprising: a plurality of central structural elements, each ofthe plurality of central structural elements comprising two parallelwelded wire lattice mats, straight bridging wires welded at each end tothe two wire lattice mats holding the wire lattice mats at apredetermined mutual separation and an insulating member penetrated bythe bridging wires arranged with its cover surfaces parallel to the wirelattice mats and at a predetermined distance to the wire lattice mats;shuttering walls arranged on opposing sides of said plurality of centralstructural elements, each of said shuttering walls comprising aplurality of sections connectable to one another; a plurality of spacingmembers composed of rustproof materials arranged and dimensioned fordefining a spacing between each of said plurality of structural elementsand said shuttering walls for receiving concrete for forming concreteshells; and a base plate, wherein lower ones of said plurality ofcentral structural elements are fixed firmly in position withreinforcing irons anchored in said base plate.